Patent document 1 publicized a semiconductor element with a light emitting function. As shown in FIG. 31 patent document 1 publicized such semiconductor element with a thyristor structure, comprising layers of p-type first layer “312”, p-type second layer “314”, n-type third layer “316”, p-type fourth layer “318”, n-type fifth layer “320” and n-type sixth layer “322”.
In the semiconductor element, a semiconductor material layer is set so that: during “ON” state when the current passing from anode to cathode, minority carriers implanted through a forward pn junction emit light and recombine. Thus, it is possible to form a 3-terminal light emitting element in “ON” state.
It may refer to patent document 1 of Japan patent publication 2001-68726.
In the 3-terminal light emitting element with such structure mentioned above, however, in order to enable the thyristor to operate well, minority carriers implanted into a gate layer are desired to pass through the gate layer without recombining vigorously. Further, in a light emitting operation, the minority carriers implanted into an active layer should be closed in this layer to improve a carrier density so as to enable the light emitting operation to be more efficient.
In order to close carriers into the active layer, besides setting an energy barrier on a semiconductor layer interface that contacts the active layer, a semiconductor layer with a certain thickness still needs to be set. However, the setting mentioned above is just contrary to that the minority carriers pass through the gate layer without recombining vigorously. Thereby, it fails to improve gate control performance.
Therefore, it is difficult for a conventional 3-terminal light emitting element to optimize simultaneously both an electrical characteristic and a light emitting characteristic.